The Casio G-Shock Mudmaster GSG-100-1A is a rugged solar-powered analog-digital watch designed for extreme outdoor conditions. Part of the Master of G series, this model features Tough Solar power technology that converts both sunlight and artificial light into energy, eliminating the need for battery replacements. The watch measures 56.2 x 54.9 x 17.3 mm and weighs just 88 grams despite its robust construction.

Key features include mud-resistant buttons that prevent dirt and debris from entering the case, and 200-meter water resistance for swimming and water sports. The innovative Neon Illuminator double LED light system combines a standard LED backlight with a black light LED that illuminates six hour markers and the hand tips for enhanced visibility in low-light conditions. Neobrite luminous hands and markers provide additional visibility.

Functional capabilities include world time with 31 time zones and 48 cities, a 1/100-second stopwatch, countdown timer up to 100 minutes, five daily alarms, and a full auto-calendar. The hand shift function moves the analog hands out of the way when using digital displays. Originally launched in 2018 with a retail price of $330, this discontinued model remains popular among G-Shock enthusiasts for its balance of features and durability.